Compare methods

	Population Potential Model	Spatial Interaction Model
Field	Human Geography	Spatial analysis
Family	Process / pipeline	Regression model
Year of origin	1947	1971
Originator	John Q. Stewart	Alan Wilson (entropy-maximizing family)
Type	Social-physics measure of the cumulative influence of population at a location	Model of flows between spatial origins and destinations
Seminal source	Stewart, J. Q. (1947). Empirical mathematical rules concerning the distribution and equilibrium of population. Geographical Review, 37(3), 461–485.	Wilson, A. G. (1971). A family of spatial interaction models, and associated developments. Environment and Planning A, 3(1), 1–32.
Aliases	Potential of Population, Market Potential Model, Demographic Potential, Stewart Potential	gravity model, spatial interaction model, competing destinations model, mekânsal etkileşim modeli
Related	4	4
Summary	The population potential model measures the cumulative influence that all of a region's population exerts on a given point, weighting each place's population inversely by its distance. Introduced by the astronomer-turned-social-scientist John Q. Stewart in 1947 as part of his 'social physics', it borrows the gravitational-potential analogy from physics: every population mass contributes potential at a point in proportion to its size and in inverse proportion to its distance. Summed across all places, the result is a smooth potential surface that maps relative accessibility, market reach, and demographic pressure.	Spatial interaction models predict the volume of flows — migrants, commuters, shoppers, trade, trips — between origins and destinations as a function of the size of each place and the distance or cost separating them. By analogy to Newton's gravity, interaction rises with the 'mass' of origin and destination and falls with separation, and Wilson's 1971 entropy-maximizing family put these models on a rigorous footing for transport, migration, and retail analysis.